Laser navigation module

ABSTRACT

Disclosed herein is a laser navigation module. A light source emits a laser beam. A housing includes an IR window and a transparent or semitransparent part. The IR window transmits or reflects the laser beam emitted from the light source, and also interrupts transmission of external visible rays. The transparent or semitransparent part allows light emitted in the housing to be transmitted out of the housing. An illuminator is installed in the housing. A light diffusion unit transmits the light emitted from the illuminator to the housing. A re-reflective layer is formed on the upper surface of the light diffusion unit.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No.10-2010-0093354, filed Sep. 27, 2010, entitled “Laser NavigationModule”, which is hereby incorporated by reference in its entirety intothis application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a laser navigation module.

2. Description of the Related Art

Generally, personal mobile telecommunication terminals, such as cellularphones or smartphones, include user interfaces that use keypads. Thekeypads include input buttons pertaining to numerals, characters anddirections.

Recently, the commercialization of wireless internet services, such asWIBRO (wireless broadband) services, has led to the development ofpersonal mobile telecommunication terminals which use windows operatingsystems supporting GUIs (graphical user interfaces).

This means that operating systems supporting GUIs are used as the userinterfaces of personal mobile telecommunication terminals. Hence, thereis a demand for the development of input devices which are suitable forsuch mobile telecommunication terminals and are devised such that usersto easily and conveniently use them. To achieve this, various devices,such as touch keys, joysticks, and optical pointing devices, etc. havebeen developed, the touch keys being configured such that keypads aredisplayed on the displays of mobile telecommunication terminals andusers input signals using the keypads. Laser navigation modulesincluding windows and lids are also representative examples of thesedevices.

However, conventional laser navigation modules have no separateilluminators. Thus, users cannot easily use the modules in dark places.

In detail, FIG. 1 is an exploded perspective view showing a lasernavigation module 100, which is an input device for mobiletelecommunication terminals, according to a conventional technique. Asshown in FIG. 1, the laser navigation module 100 includes an IR window110, a housing 120, a lid 130, a control IC chip 140, a PCB (printedcircuit board) 150 and a dome switch 160.

A laser beam emitted from a light source is transmitted through the IRwindow 110 and then reflected off the body of a user, for example,his/her hand. The IR window 110 is installed in the housing 120.

The lid 130 is disposed below the IR window 110. The lid 130 functionsas a screen which blocks transmission of external stray light. The lid130 has a stepped portion 131, a circular hole 132 and a rectangularpassing hole 133. The lid 130 can be more closely coupled to the housing110 by the stepped portion 131. A laser beam emitted from the lightsource is transmitted through the circular hole 132. The laser beam isreflected or refracted by the body of the user that is in contact withthe IR window. The reflected or refracted laser beam passes through therectangular passing hole 133.

The control IC chip 140 includes a VCSEL (vertical-cavitysurface-emitting laser) 141 which is the light source. The control ICchip 140 calculates the displacement value of a laser beam which isreflected or refracted by the IR window 110. The control IC chip 140 ismounted to the PCB 150. The dome switch 160 is coupled to the lowersurface of the PCB 150. The dome switch 160 senses pressure applied tothe IR window 110 by the user and transmits the signal selected by theuser to a control unit (not shown) which is disposed below the domeswitch 160.

However, this conventional laser navigation module has no separateilluminator and so is inconvenient to use in dark places. Although anilluminator may be provided separately outside of the laser navigationmodule, the separate illuminator cannot be easily installed in the lasernavigation module, because the laser navigation module is too small.Furthermore, even if the illuminator could be installed in the lasernavigation module, it is very difficult to manufacture a lasernavigation module that uniformly transmits light emitted from theilluminator to the outside of the laser navigation module.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a lasernavigation module which includes an illuminator installed in a housing,and a light diffusion unit which diffuses light emitted from theilluminator. A re-reflective layer is formed on an upper surface of thelight diffusion unit and another re-reflective layer is selectivelyformed under a lower surface of the light diffusion unit, so that lightcan be uniformly emitted out of the laser navigation module by there-reflection of light, thus facilitating use of the laser navigationmodule even in dark places.

In a laser navigation module according to an embodiment of the presentinvention, a light source emits a laser beam. A housing includes an IRwindow and a transparent or semitransparent part. The IR windowtransmits or reflects the laser beam emitted from the light source. TheIR window interrupts transmission of external visible rays. Thetransparent or semitransparent part allows light emitted from in thehousing to be transmitted out of the housing. An illuminator isinstalled in the housing. A light diffusion unit transmits the lightemitted from the illuminator to the housing. A re-reflective layer isformed on an upper surface of the light diffusion unit.

The light diffusion unit may have a through hole through which the laserbeams emitted from the light source pass. A protrusion may be disposedat a position corresponding to the illuminator. The protrusion maychange a direction of the light emitted from the illuminator. There-reflective layer may have an opening at a position corresponding tothe through hole.

The re-reflective layer may be formed on a portion of the upper surfaceof the light diffusion unit other than a perimeter of the upper surfaceof the light diffusion unit. The re-reflective layer may comprise alayer coated with silver (Ag).

The light diffusion unit may have a through hole through which the laserbeams emitted from the light source pass. A protrusion may be disposedat a position corresponding to the illuminator. The protrusion maychange a direction of the light emitted from the illuminator. There-reflective layer may be formed on a portion of the upper surface ofthe light diffusion unit other than portions corresponding to thethrough hole and the protrusion. A lower re-reflective layer may befurther formed on the light diffusion unit at a position facing theilluminator.

The lower re-reflective layer may have an opening corresponding to thethrough hole and the protrusion of the light diffusion unit.

The light diffusion unit may comprise two portions including a firstportion having the protrusion, and a second portion other than the firstportion having the protrusion. The re-reflective layer may be formed onthe second portion. The lower re-reflective layer may comprise a mirrortape coated with silver (Ag).

The laser navigation module may further include a lid disposed below theIR window. The lid may block transmission of stray external light. Acircular hole and a rectangular passing hole may be formed in the lid.The control IC chip may have the light source. The control IC chip maycalculate a displacement value of the laser beam that is reflected orrefracted by the IR window and returned. The control IC chip may bemounted to a printed circuit board. A dome switch may be provided belowthe printed circuit board.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will be more clearly understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is an exploded perspective view showing a laser navigation moduleaccording to a conventional technique;

FIG. 2 is a sectional view of a laser navigation module, according tothe present invention;

FIG. 3 is a perspective view of a light diffusion unit of a lasernavigation module according to a first embodiment of the presentinvention;

FIG. 4 is an exploded perspective view showing a light diffusion unitand mirror tape of a laser navigation module according to a secondembodiment of the present invention; and

FIG. 5 is an exploded perspective view showing a light diffusion unitand mirror tape of a laser navigation module according to a thirdembodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference now should be made to the drawings, in which the samereference numerals are used throughout the different drawings todesignate the same or similar components. In the following description,when it is determined that the detailed description of the conventionalfunction and conventional structure would confuse the gist of thepresent invention, such a description may be omitted. Furthermore, itwill be understood that, although the terms “first”, “second” etc. maybe used herein to describe various elements, components, regions, layersand/or sections, these elements, components, regions, layers and/orsections should not be limited by these terms. These terms are only usedto distinguish one element, component, region, layer or section fromanother element, component, region, layer or section.

Hereinafter, embodiments of the present invention will be described indetail with reference to the attached drawings.

FIG. 2 is a sectional view of a laser navigation module, according to anembodiment of the present invention. AS shown in FIG. 2, the lasernavigation module 200 includes an IR window 210, a housing 220, a VCSEL(vertical-cavity surface-emitting laser, not shown), a lid 230, acontrol IC chip 240, an illuminator 250, a light diffusion unit 260, aPCB (printed circuit board) 270 and a dome switch (not shown).

According to a stacking sequence, the PCB 270 is placed on the domeswitch (not shown), and the control IC chip 240, the VCSEL (not shown)and the illuminator 250 are mounted to an upper surface of the PCB 270.The lid 230 is coupled to the PCB 270 and disposed above the VCSEL andthe illuminator. Furthermore, the light diffusion unit 260 is providedabove the lid 230. The housing 220 provided with the IR window 210 iscoupled to an upper surface of the light diffusion unit 260.

In detail, the lid 230 is a screen which blocks the transmission ofexternal stray light. A circular hole (not shown) and a rectangularpassing hole are formed in the lid 230 so that a laser beam emitted fromthe VCSEL (the light source) passes through the circular hole and therectangular passing hole. A hole 231 is formed through the lid 230 sothat light emitted from the illuminator 250 passes through the hole 231.

The control IC chip 240 includes the VCSEL and calculates a displacementvalue of a laser beam which is reflected or refracted by the IR window110. The VCSEL is the light source which emits the laser beam which istransmitted through or reflected by the IR window 210. The IR window 210interrupts transmission of external visible rays.

The illuminator 250 emits light out of the housing 220.

The light diffusion unit 260 includes a protrusion 261 which changes apath of light emitted from the illuminator 250 and diffuses the light,and a through hole (262 of FIG. 3) through which a laser beam emittedfrom the VCSEL passes.

In an embodiment, an LED is used as the illuminator 250.

The housing 220 of the laser navigation module according to the presentinvention is made of transparent or semitransparent material such thatlight emitted from the illuminator 250 is transmitted out of the housing220.

FIG. 3 is a perspective view of a light diffusion unit 260 of the lasernavigation module according to a first embodiment of the presentinvention. As shown in FIG. 3, the light diffusion unit 260 is disposedat a position corresponding to the illuminator 250. The light diffusionunit 260 includes a protrusion 261 which changes the path of lightemitted from the illuminator, and a through hole 262 through which alaser beam emitted from the VCSEL (not shown) that is the light sourcepasses. Because the protrusion 261 is configured to correspond to theilluminator, if the illuminator comprises a plurality of illuminators,the protrusion 261 also comprises a plurality of protrusions 261 each ofwhich corresponds to a respective illuminator.

Furthermore, a re-reflective layer 263 is formed on an upper surface ofthe light diffusion unit 260. In this embodiment, the re-reflectivelayer 263 is formed on a portion of the upper surface of the lightdiffusion unit 260 other than the perimeter of the upper surface.Thereby, light emitted from the illuminator is transmitted to thehousing through the perimeter of the light diffusion unit 260. Inaddition, the re-reflective layer 263 has an opening at a positioncorresponding to the through hole 262 of the light diffusion unit 260.In the embodiment, the re-reflective layer 263 is coated with silver(Ag). Moreover, to emit light from the illuminator out of the housingthrough the light diffusion unit 260 with uniform brightness, it isdesirable that the re-reflective layer 263 be designed in variouspatterns and then the optimal pattern be selected by testing thebrightness of light diffused out of the housing.

FIG. 4 is an exploded perspective view showing a light diffusion unit260 and mirror tape 280 of a laser navigation module according to asecond embodiment of the present invention. As shown in FIG. 4, thelaser navigation module according to the second embodiment furtherincludes a lower re-reflective layer which is formed under a lowersurface of the light diffusion unit 260 facing the illuminator. Thelower re-reflective layer is realized by mirror tape 280 coated withsilver (Ag).

The mirror tape 280 re-reflects light reflected off of an upper surfaceof the light diffusion unit 260.

Furthermore, taking into account the fact that a lot of light isreflected off of a region adjacent to the protrusion 261 of the lightdiffusion unit 260, the mirror tape 280 should be formed on a portion ofthe light diffusion unit 260 other than the region adjacent to theprotrusion 261. Thereby, uniform diffusion of light and uniformbrightness can be ensured. In the embodiment of FIG. 4, the lightdiffusion unit 260 has the region including the protrusion 261, and theother region which does not include the protrusion 261. The mirror tape280 is formed on the region that does not include the protrusion. Anopening 281 is formed in the mirror tape 280 at a position correspondingto the through hole 262.

Moreover, the re-reflective layer can be realized by various methods,for example, it may be realized by the mirror tape or, alternatively, itmay be realized by applying coating material onto the light diffusionunit 260.

FIG. 5 is an exploded perspective view showing a light diffusion unit260 and mirror tape 280 of a laser navigation module according to athird embodiment of the present invention. As shown in FIG. 5, are-reflective layer is partially formed at a side of the light diffusionunit 260 that faces the illuminator. The re-reflective layer maycomprise a mirror tape 280 coated with silver (Ag). In this case, there-reflective layer can be formed by attaching the mirror tape 280 tothe corresponding surface of the light diffusion unit 260. The mirrortape 280 has an opening 281 corresponding to the protrusion 261, andanother opening 282 corresponding to the through hole 261. FIG. 5illustrates the mirror tape 280 having the shape corresponding to thelight diffusion unit 260 provided with two protrusions 261. In detail,to more effectively couple the mirror tape 280 to the light diffusionunit 260, the mirror tape 280 has a first opening 281 corresponding toone protrusion 261, and a second opening 282 corresponding to the otherprotrusion and the through hole 262. Furthermore, the re-reflectivelayer can be realized by various other methods, for example, it may berealized by applying coating material to the light diffusion unit 260.

As described above, in a laser navigation module according to thepresent invention, an illuminator is installed in a housing. A lightdiffusion unit diffuses light emitted from the illuminator. Are-reflective layer is formed on an upper surface of the light diffusionunit and a lower re-reflective layer is formed under a lower surface ofthe light diffusion unit. Hence, light can be uniformly emitted out ofthe laser navigation module by the re-reflection of light, thusfacilitating the use of the laser navigation module even in dark places.

Although the embodiment of the present invention has been disclosed forillustrative purposes, it will be appreciated that the laser navigationmodule according to the invention is not limited thereto, and thoseskilled in the art will appreciate that various modifications, additionsand substitutions are possible, without departing from the scope andspirit of the invention.

1. A laser navigation module, comprising: a light source emitting alaser beam; a housing, comprising: an IR window transmitting orreflecting the laser beam emitted from the light source, the IR windowinterrupting transmission of external visible rays; and a transparent orsemitransparent part allowing light emitted from in the housing to betransmitted out of the housing; an illuminator installed in the housing;and a light diffusion unit transmitting the light emitted from theilluminator to the housing, with a re-reflective layer formed on anupper surface of the light diffusion unit.
 2. The laser navigationmodule as set forth in claim 1, wherein the light diffusion unitcomprises: a through hole through which the laser beams emitted from thelight source pass; and a protrusion disposed at a position correspondingto the illuminator, the protrusion changing a direction of the lightemitted from the illuminator, and the re-reflective layer has an openingat a position corresponding to the through hole.
 3. The laser navigationmodule as set forth in claim 2, wherein the re-reflective layer isformed on a portion of the upper surface of the light diffusion unitother than a perimeter of the upper surface of the light diffusion unit.4. The laser navigation module as set forth in claim 1, wherein there-reflective layer comprises a layer coated with silver (Ag).
 5. Thelaser navigation module as set forth in claim 1, wherein the lightdiffusion unit comprises: a through hole through which the laser beamsemitted from the light source pass; and a protrusion disposed at aposition corresponding to the illuminator, the protrusion changing adirection of the light emitted from the illuminator, and there-reflective layer is formed on a portion of the upper surface of thelight diffusion unit other than portions corresponding to the throughhole and the protrusion, and a lower re-reflective layer is furtherformed on the light diffusion unit at a position facing the illuminator.6. The laser navigation module as set forth in claim 5, wherein thelower re-reflective layer has an opening corresponding to the throughhole and the protrusion of the light diffusion unit.
 7. The lasernavigation module as set forth in claim 5, wherein the light diffusionunit comprises two portions including a first portion having theprotrusion, and a second portion other than the first portion having theprotrusion, and the re-reflective layer is formed on the second portion.8. The laser navigation module as set forth in claim 5, wherein thelower re-reflective layer comprises a mirror tape coated with silver(Ag).
 9. The laser navigation module as set forth in claim 1, furthercomprising: a lid disposed below the IR window, the lid blockingtransmission of stray external light, with a circular hole and arectangular passing hole formed in the lid; a control IC chip having thelight source, the control IC chip calculating a displacement value ofthe laser beam that is reflected or refracted by the IR window andreturned; a printed circuit board to which the control IC chip ismounted; and a dome switch provided below the printed circuit board.